Preliminary construction method of in-plant trench of nuclear power plant

ABSTRACT

The embodiment of the present invention is a preliminary construction method of an in-plant trench of a nuclear power plant, the method. The method includes: constructing a plurality of buildings for generating an atomic energy; constructing a trench between the buildings via a platform configured to adjust a level of the trench with an installation level of the trench; and backfilling an area between a ground and the trench, after the construction of the trench.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2011-131516, filed on Jun. 13, 2011, the entire contents of which are incorporated herein by reference.

FIELD

The present invention relates to a construction method of an in-plant trench of a nuclear power plant.

BACKGROUND

The structure of a nuclear power plant is described with reference to FIGS. 11 to 13. FIG. 11 is a schematic perspective view of a nuclear power plant. FIG. 12 is a schematic structural side view of the nuclear power plant. As shown in FIGS. 11 and 12, the nuclear power plant includes a nuclear reactor building 51, an auxiliary boiler building 58, a trench 52, a pipe 53 and a cable tray 54. The nuclear reactor building 51 and the auxiliary boiler building 58 are disposed on a rock mass 55. The trench 52 is constructed on a backfill part 57A between the nuclear reactor building 51 and the auxiliary boiler building 58. The pipe 53 and the cable tray 54 connect the nuclear reactor building 51 and the auxiliary boiler building 58 to each other, through the inside of the trench 52. FIG. 13 is a schematic sectional view of the trench 52. As shown in FIG. 13, the inside of the trench 52 is adapted to contain the pipe 53 and the cable tray 54.

Further, a construction method of an in-plant trench in a conventional construction of a nuclear power plant is described with reference to FIGS. 14 to 17. FIGS. 14 to 17 are schematic views showing construction procedures of the conventional construction method of a nuclear power plant. As shown in FIG. 14, a ground 56 is firstly excavated, until the rock mass 55 is exposed. Then, the nuclear reactor building 51 and the auxiliary boiler building 58 are constructed on the rock mass 55. At this time, an unexcavated portion 63 generally remains. Then, as shown in FIG. 15, an area on the rock mass 55 around the nuclear reactor building 51 and the auxiliary boiler building 58 and/or an area on the unexcavated portion 63 is backfilled with dirt and/or sands (this area is referred to as “backfill part 57A”). Then, as shown in FIG. 16, the trench 52 is constructed on the backfill part 57A. Then, as shown in FIG. 17, after the construction of the trench 52 has been completed, construction of the pipe 53 and the cable tray 54 is performed. Thus, the nuclear reactor building 51 and the auxiliary boiler building 58 are connected to each other. In addition, after the trench 52 excavation has been completed, bottom of the trench is backfilled with dirt and/or sand up to a height corresponding to the ground 56 (this area is referred to as “backfill part 57B”). Then, after the cable tray 54 has been installed, cables are laid, and a system test is conducted.

As described above, after the construction of the nuclear reactor building 51 and the auxiliary boiler building 58 has been completed, the area on the rock mass 55 around the nuclear reactor building 51 and the auxiliary boiler building 58 and/or the area on the unexcavated portion 63 is backfilled with dirt and/or sands, and then the construction of the trench 52 is performed. Thus, so far the system test for the nuclear reactor building 51 and the auxiliary boiler building 58 cannot be conducted at an earlier stage, whereby there is a problem in that a long term is required for completion of the construction of an atomic power plant until completion of installation of pipe 53 and cable tray 54 as described the above.

On the other hand, Patent Document 1 discloses a package module for storing an electric equipment for facilitating a wiring operation (Patent Document 1: JP2005-150433A).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a construction procedure 1 in a first embodiment of a preliminary construction method of an in-plant trench of a nuclear power plant according to the present invention;

FIG. 2 is a schematic view showing a construction procedure 2 in the first embodiment;

FIG. 3 is a schematic view showing a construction procedure 3 in the first embodiment;

FIG. 4 is a schematic view showing a construction procedure 4 in the first embodiment;

FIG. 5 is a schematic view showing a construction procedure 5 in the first embodiment;

FIG. 6 is a view showing a comparison between a construction term according to the first embodiment and a construction term according to the conventional construction method;

FIG. 7 is a schematic view showing a construction procedure 1 in a second embodiment of the preliminary construction method of an in-plant trench of a nuclear power plant of the present invention;

FIG. 8 is a schematic view showing a construction procedure 2 in the second embodiment;

FIG. 9 is a schematic view showing a construction procedure 3 in the second embodiment;

FIG. 10 is a schematic view showing a construction procedure 4 in the second embodiment;

FIG. 11 is a schematic structural perspective view of a nuclear power plant;

FIG. 12 is a schematic structural side view of the nuclear power plant;

FIG. 13 is a schematic sectional view of a trench;

FIG. 14 is a schematic view showing a construction procedure 1 of the conventional construction method of a nuclear power plant;

FIG. 15 is a schematic view showing a construction procedure 2 of the conventional construction method of a nuclear power plant;

FIG. 16 is a schematic view showing a construction procedure 3 of the conventional construction method of a nuclear power plant; and

FIG. 17 is a schematic view showing a construction procedure 4 of the conventional construction method of a nuclear power plant.

DETAILED DESCRIPTION

Embodiments will now be explained with reference to the attached drawings.

The embodiments of the present invention has been made in view of the above problem so as to effectively solve the same. The object of the embodiments is to provide a preliminary construction method of an in-plant trench of a nuclear power plant which can allow construction of a trench at an earlier stage, after completion of construction of a nuclear reactor building.

One embodiment of the present invention is a preliminary construction method of an in-plant trench of a nuclear power plant. The method includes: constructing a plurality of buildings for generating an atomic energy; constructing a trench between the buildings via a platform configured to adjust a level of the trench with an installation level of the trench; and backfilling an area between a ground and the trench, after the construction of the trench.

According to the embodiment, the installation of the trench can be performed before the bottom of the trench is backfilled with dirt and/or sand up to a height corresponding to the installation level of the trench. Thus, installation of a pipe, a cable tray and so on in the trench can be executed at an earlier stage. Thus, a system test between the buildings can be conducted at an earlier stage, whereby a term required for completing the construction of a nuclear power plant can be shortened.

Preferably, the platform is previously imposed on the trench, and thereafter the construction of the trench is performed. In this case, since the imposition of the platform can be performed before completion of the construction of the buildings, the construction of the trench can be performed at an earlier stage. That is to say, a term required for completing the construction of a nuclear power plant can be shortened.

On the other hand, there is a case in which it is preferable that the platform is installed with respect to the ground, and thereafter the construction of the trench is performed. For example, such an embodiment is preferred when a part of a ground on which a trench is installed is significantly rough and/or when it is difficult to previously impose a platform on a trench in a yard area.

Preferably, the trench is structured as a trench module with which at least a pipe or a cable is previously integrated. In this case, installation of the pipe, the cable tray and so on in the trench can be executed at an earlier stage. As a result, a term required for completing the construction of a nuclear power plant can be shortened.

A first embodiment of the present invention is described herebelow with reference to the drawings.

FIGS. 1 to 5 are schematic views showing construction procedures 1 to 5 in the first embodiment of a preliminary construction method of an in-plant trench of a nuclear power plant according to the present invention. FIG. 6 is a view showing a comparison between a construction term according to the first embodiment and a construction term according to the conventional construction method.

As shown in FIG. 1, a ground 6 is firstly excavated until a rock mass 5 is exposed. Then, a nuclear reactor building 1 and an auxiliary boiler building 8 are constructed on the rock mass 5.

Then, in order to adjust a level of a trench or tunnel 2 with an installation level of the trench 2, a platform for installation 10 is made in conformity to the shape of an unexcavated portion 13. Then, the platform for installation 10 is imposed on or coupled to the trench 2. The trench 2, on which the platform for installation 10 has been imposed, is structured as an integrated trench module 11 containing a pipe 3 and a cable tray 4. As can be understood from FIG. 6, before completion of the construction of the nuclear reactor building 1 and the auxiliary boiler building 8, the imposition of the platform can be performed.

Then, as shown in FIGS. 2 and 3, the trench module 11 is installed on the rock mass 5 and the unexcavated portion 13 by means of a crane 12.

Then, as shown in FIG. 4, after the construction of the trench module 11 has been completed, unconnected portions of the pipe 3 and the cable tray 4, which are to connect the nuclear reactor building 1 and the auxiliary boiler building 8, are connected to the nuclear reactor building 1 and the auxiliary boiler building 8. Thus, the nuclear reactor building 1 and the auxiliary boiler building 8 are connected to each other via the trench or tunnel 2. With the use of the integrated trench module 11, the installation of the pipe, the cable tray and so on can be performed at an earlier stage.

On the other hand, as shown in FIG. 5, after the construction of the nuclear reactor building 1 and the auxiliary boiler building 8 has been completed, backfilling of the bottom of the trench with dirt and/or sand up to a height corresponding to the ground 6 is started (backfill parts 7A and 7B). Then, after the cable tray 4 has been constructed, a cable is laid, and a system test is conducted.

As can be understood from FIG. 6, according to this embodiment, the construction of the trench can be performed, before the dirt and/or sand are backfilled up to a height corresponding to the installation level of the trench. Thus, the installation of the pipe, the cable tray and so on in the trench can be performed at an earlier stage. Further, the backfilling of the dirt and/or sands can be performed simultaneously with the installation of the pipe 3 and the cable tray 4. Thus, the system test between the buildings can be conducted at an earlier stage, whereby a term required for completing the construction of a nuclear power plant can be shortened.

Next, a second embodiment of the present invention is described with reference to the drawings.

This embodiment is available when a part of a ground on which a trench or tunnel is installed is significantly rough and/or when it is difficult to previously impose or couple a platform on a trench in a yard area.

FIGS. 7 to 10 are schematic views showing construction procedures 1 to 4 in the second embodiment of the preliminary construction method of an in-plant trench of a nuclear power plant according to the present invention.

As show in FIG. 7, a ground 6 is firstly excavated until a rock mass 5 is exposed. Then, a nuclear reactor building 1 and an auxiliary boiler building 8 are constructed on the rock mass 5.

Then, as shown in FIG. 8, in order to adjust a level of a trench 2 with an installation level of the trench 2, a platform 14 is installed on the rock mass 5 and an unexcavated portion 13 in conformity to the shape of the unexcavated portion 13. The trench 2 is structured as a second integrated trench module 15 containing a pipe 3 and a cable tray 4.

Then, as shown in FIGS. 9 and 10, the second trench module 15 is installed on the rock mass 5 and the platform 10 above the unexcavated portion 13 by means of a crane 12.

Then, after the construction of the second trench module 15 has been completed, unconnected portions of the pipe 3 and the cable tray 4, which are to connect the nuclear reactor building 1 and the auxiliary boiler building 8, are connected to the nuclear reactor building 1 and the auxiliary boiler building 8. Thus, the nuclear reactor building 1 and the auxiliary boiler building 8 are connected to each other. With the use of the second integrated trench module 15, the installation of the pipe, the cable tray and so on can be performed at an earlier stage.

On the other hand, after the construction of the platform 14 has been completed, backfilling of the bottom of the trench with dirt and/or sand up to a height corresponding to the ground 6 is started (backfill parts 7A and 7B). Then, after the cable tray 4 has been constructed, a cable is laid, and a system test is conducted.

According to this embodiment, even when a part of the ground 6 on which the trench 2 is installed is significantly rough and/or when it is difficult to previously impose a platform on the trench 2 in a yard area, the installation of the trench 2 can be executed before the bottom of the trench is backfilled with dirt and/or sand up to a height corresponding to the installation level of the trench 2. Thus, the installation of the pipe 3, the cable tray 4 and so on in the trench 2 can be performed at an earlier stage. Further, the backfilling of the bottom of the trench with dirt and/or sand can be performed simultaneously with the installation of the pipe 3 and the cable tray 4. Thus, the system test between the buildings 1, 8 can be conducted at an earlier stage, whereby a term required for completing the construction of a nuclear power plant can be shortened.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fail within the scope and spirit of the inventions. 

1. A preliminary construction method of an in-plant trench of a nuclear power plant, the method comprising: constructing a plurality of buildings for generating an atomic energy; constructing a trench between the buildings via a platform configured to adjust a level of the trench with an installation level of the trench; and backfilling an area between a ground and the trench, after the construction of the trench.
 2. The preliminary construction method of an in-plant trench of a nuclear power plant according to claim 1, wherein the platform is previously imposed on the trench, and thereafter the construction of the trench is executed.
 3. The preliminary construction method of an in-plant trench of a nuclear power plant according to claim 1, wherein the platform is installed with respect to the ground, and thereafter the construction of the trench is executed.
 4. The preliminary construction method of an in-plant trench of a nuclear power plant according to claim 1, wherein the trench is structured as a trench module with which at least a pipe or a cable is previously integrated. 